Alouette/ISIS: How it all Began

"Ladies and gentlemen, before beginning, I would like
to say a few words on behalf of all those, in government and industry, who worked on the
Alouette and ISIS program. I amnot sure that I can really adequately express how deeply we
appreciate the honour and recognition which this ceremony represents. The program, and
people who worked on it have received many awards over the years. However, this
international recognition from the IEEE is especially gratifying. At the beginning we
certainly had nothing like this in mind and I only wish that some of those early pioneers
who contributed so much to the program, and who have now passed away, could be with us
today. In particular, I think of Frank Davies (Chief Superintendent of the Defence
Research Telecommunications Establishment, Ottawa), John Chapman, Eldon Warren, Bert
Walker, and David Florida.

Let me now turn to my address. It will not be a detailed
technical presentation but more of a personal perspective from someone who was there from
the beginning. We had setbacks. In real life, successful programs are rarely the tidy
affairs they seem when written up in scholarly journals.

I will begin with the Defence Research Telecommunications
Establishment (DRTE), Ottawa. This is where the program was conceived and where the first
two satellites were designed and built. DRTE had its origins in ionospheric sounding
activities carried out by the Canadian Armed Forces and NRC during WW II. Before the
satellite era radio propagation via the ionosphere was the main method of long distance
communications, other than via landlines and underwater cables. Subsequently DRTE became a
leader in the field of ionospheric research and by the late 1950s had become one of the
foremost research establishments on the continent, with Radiophysics and Electronics
laboratories that were on a par with any in the world.

With the launching of Sputnik in October 1957 it was
realised at DRTE and elsewhere that a satellite-borne radar would provide a very powerful
means of exploring the ionosphere from above (topside sounding), and that this could have
important implications for long distance radio communications. Also, Bert Walker of the
Canadian Joint Staff in Washington reported early in 1958 that the Naval Research
Laboratory would welcome proposals from Canada for experiments in satellites and suggested
that DRTE should respond.

.

The antenna construction site

At a meeting in October 1958, called by H.G. Booker of
Cornell University to discuss ionospheric experiments in satellites, a number of groups in
the USA and two in Canada, including DRTE, indicated their interest in topside soundings.
This meeting resulted in DRTE submitting a proposal, to build a topside sounder satellite,
to the newly created NASA in late 1958. Not a simple sounder operating on a few
frequencies but a swept-frequency one that duplicated in a satellite the ionospheric
sounders then used on the ground. The proposal was accepted and Canada's satellite program
was born; without it seems much formality. Sputnik and the cold war produced a sense of
urgency.

It was to be a cooperative undertaking between Canada and
the U.S. with each country paying its own costs in the project. Canada subsequently
undertook to provide a prototype and two flight spacecraft, and three ground stations
including a master ground station and data processing centre in Ottawa. Canada also
undertook to operate four ground stations for at least a year and exchange copies of all
ionograms with cooperating agencies. The U.K. joined the program later and provided four
telemetry stations.

The United States agreed to provide the launch vehicle,
launch facilities, and a world-wide network of ground stations. The principal objectives
of the program were to:

(1) develop a Canadian space capability;

(2) acquire new data for the engineering of high frequency
radio communication links;

(3) acquire a better understanding of the properties of the
ionosphere for scattering and deflection of radar beams.

NASA officials were nevertheless, sceptical (as indeed were
some Canadians). They were convinced that it was too difficult to build the first
Space-Based Radar (and a swept frequency one as well) at that time. The Central Radio and
Propagation Laboratory (CRPL) at Boulder, Colorado agreed with the NASA view that the
proposal was too ambitious, so their report recommended a fixed-frequency experiment as a
first generation topside sounder and that DRTE "be encouraged to develop its
swept-frequency system as a second generation experiment".

.

The erecting of the antenna

The rest is history; the CRPL/NASA fixed frequency
satellite (S-48) suffered delays, the Canadian satellite (S-27) kept more or less on
schedule; S-48 suffered more delays; S-27 was launched on 29 September 1962, to become
Alouette I, the first satellite to be designed and built by a nation other than the United
States or the Soviet Union. S-48 was eventually launched in August 1964, NASA later
admitted publicly that they and CRPL were so convinced that it could not possibly function
for more than an hour or two, if at all, that they had made no plans to use data from it.
In fact Alouette I, constructed at a time when most satellites had a useful lifespan of a
few months, continued to function and provided a wealth of data for ten years before it
was turned off from the ground.

Text books on space technology and the in-orbit radiation
environment were non-existent and the open literature and internal NASA reports were
sparse. The young Canadian engineering team, at one point referred to as the "farm
team", had no prior experience in the design of space systems and hardware but was
highly skilled in the emerging area of solid state electronics. It also had the great
advantage of being in day-to-day contact with world class scientists in the Radio Physics
Laboratory. Finally there was the excellent support received from the emerging Canadian
space industry and the close working relationships and trust that developed with our NASA,
CRPL and AIL (Airborne Instrument Laboratories) colleagues. AIL built the U.S. topside
sounder. Indeed we dealt with our U.S. colleagues as if we were all part of one big
family.

To continue, little of the technology developed for
ground-based sounders was directly applicable. Aside from the use of vacuum tube systems
with their associated reliability problems and weight, size and power consumption, these
sounders typically used large separate antennas for reception and transmission which were
physically separated from one another in order to minimise RF interference between their
transmitters and receivers.

Initially it was thought that these problems might best be
solved using a swept-frequency CW radar instead of a more conventional pulse system and a
good deal of time was wasted on this approach. The development of a vacuum tube
transmitter was then undertaken but abandoned when a parallel development showed the
required performance could be obtained using transistors.

There were stormy scenes on the subject of transmitter
power. Caution said keep it low for reasons of cost, reliability and power consumption.
The bolder approach eventually prevailed and a transmitter power ten times greater than
the calculated minimum needed was finally chosen. This was a milestone decision since it
greatly eased the antenna design and the mass production of high quality ionograms.

Cosmic noise was the subject of more scenes because of its
impact on the transmitter power required for the sounder. Two attempts were made to
measure cosmic noise in Javelin rockets from Wallops Island in 1959. They failed. In 1960
a 3.8 MHz cosmic noise receiver was designed and flown on a U.S. navy TRANSIT navigation
satellite providing the first measurements of cosmic noise to be made above the
ionosphere.

.

The erected Alouette/ISIS tracking
antenna

One of the most difficult problems was the design of the
sounder antenna system which had to cover a 1-10 MHz frequency range. Four STEM (Storable
Tubular Extendible Member) devices formed two long sounding dipoles (150 feet and 75 feet
tip-to-tip). A test flight on a Javelin rocket from Wallops Island was carried out to test
the extension of a pair of STEMs in space. It was a partial success, one STEM did not
fully extend. The STEM has since become an important, multi-purpose space mechanism and
has been used on many space vehicles, including manned space flight projects. It was
developed by Spar Aerospace from an NRC design for an extendible mast antenna for use in
WW II.

The design of the telemetry system was unexpectedly
difficult. The sounder antennas generated multiple nulls in the radiation pattern of the
telemetry antenna. Because the satellite was spinning, these nulls would have produced
regular drop-outs in telemetry which in turn would have hampered data analysis and
severely reduced the value of the ionograms. The effect of the nulls was largely
eliminated through a novel design of the telemetry and command antenna system in the
satellite and by diversity reception and combining on the ground.

Nine months before launch we had no telemetry transmitter
to send the ionospheric data to the ground. A U.S. company said the specifications, due to
the sounder, were too difficult to meet. When John Stewart at RCA Victor, Montreal (now
Spar) heard of our problem, over breakfast at a conference we were both at in
Philadelphia, he said he thought his team could do it. He was told to go ahead, forget
about costs and contractual details, and get us an engineering model within two months. He
succeeded, the subsequent flight models operated flawlessly, and the design became the
standard for subsequent Canadian and U.S. ionospheric sounder satellites.

The approach taken on reliability was novel and
controversial. Little reliance was placed on statistical reliability calculations. Instead
we insisted on a thorough understanding of semiconductor devices and circuit operation and
worked closely with manufacturers to ensure that only semiconductors with median parameter
values were procured. Circuits capable of operating under much greater than expected
temperature and power supply variations were developed to counter expected and unexpected
modes of degradation and failure. The consequences of radiation damage to semiconductor
components were minimised by designing for far larger variations in transistor parameters
than was the accepted practice at the time. This was an early example of what is now known
as Robust Design. At the time critics said we would end up damaging components and
degrading reliability. Similarly on the mechanical side, deployable items were designed to
be fully tested under 1g conditions on the ground, although critics claimed this was
overdesign.

The power supply was designed for what appeared at the time
to be a very pessimistic figure of 40% degradation for solar cell charging currents, after
one year in orbit. This paid off even before launch because it allowed the Alouette design
to survive an unexpected artificial radiation belt created by a hydrogen bomb test at high
altitude over Johnston Island in the Pacific in July, 1962.

With the assistance of the Defence Research Chemical
Laboratory, Ottawa (now DREO) a major effort was made to improve the reliability of
commercially available Ni Cd batteries. This resulted in some important differences
between the Alouette and ISIS batteries and those used in U.S. spacecraft. The resulting
batteries functioned for ten years in Alouette I and II and twenty years in ISIS-I and -II
and were superior to those used in any other space program of the period. Particular
attention was paid to the design of dc-dc converters. Other problems included the design
of a novel transmit- switch and the elimination of electromagnetic interference in VLF and
HF receivers.

The electrical and mechanical design and most of the
environmental testing was done in Canada. The Canadian Armament Research and Development
Establishment, Valcartier provided the thermal-vacuum test facilities.

The De Havilland Special Products Division, later to become
Spar Aerospace Ltd, in addition to providing the STEM antennas, manufactured the satellite
structure, and performed spin and centrifuge testing. Sinclair Radio designed the
telemetry and command antenna subsystem in the spacecraft.

Within a few weeks of the launch of Alouette-I, it was
clear that the satellite would provide the comprehensive and detailed data on ionospheric
structure that was its primary mission.

This posed the problem of whether there should be an
ongoing satellite program and, if so, what form it should take. Most of the skills and
expertise responsible for the success of the satellite were in a government establishment,
and not in industry. If Canada was to reap the full benefits of space technology it needed
a strong domestic space industry. John Chapman took the lead in negotiating with NASA a
follow-up program of scientific satellites, and took action to ensure that an increasing
proportion of the design and construction work would be carried out in Canadian industry.
This led to the International Satellites for Ionospheric Studies (ISIS) programme in which
Canada and the U.S. shared the major costs for the construction and launching of four more
satellites; three Canadian and one U.S. The U.K. and seven other countries actively
participated through the provision of telemetry facilities and scientific analysis effort.
The three Canadian satellites were Alouette-II - a refurbished Alouette-I flight spare
spacecraft launched in 1965 along with a U.S. probe satellite, and two observatory
satellites ISIS-I and ISIS-II launched in 1969 and 1971 respectively. The two observatory
satellites were heavier and more complex than the Alouettes, and were prime contracted and
built in Canadian industry. They carried tape recorders, probe and particle experiments
from the U.S. and the U.K., and in the case of ISIS-II, two optical experiments. The
principal experiment in each was still the ionospheric sounder which was essentially an
upgraded version of the Alouette-I system plus a fixed frequency sounder.

A DRTE proposal for a further satellite in the series,
ISIS-C, with 375m tip-to-tip antennas, was approved by NASA. It was an ambitious program
to explore the magnetosphere but was withdrawn following the government's decision in 1968
to redirect Canada's space program from scientific to communications and remote sensing
applications of space technology.

The Alouette/ISIS program has been an immense scientific
and technological success with over 1200 papers and scientific reports published. Alouette
II operated for nearly ten years before being turned off. Operation of the ionospheric
sounders and VLF receivers in ISIS-I and -II operated for twenty years in orbit. In July,
1984, ISIS-I and ISIS-II were loaned to Japan's Communications Research Laboratory where
they were operated for another five years for research purposes. They were turned off in
1990 with the ionospheric sounders and VLF experiments still fully operational. It was the
gradual deterioration of battery capacity however that finally made impractical the
continued operation of these satellites.

The success of Alouette-I led not only to the follow-on
international program but more importantly to the establishment of the Canadian space
industry which in 1990 had annual sales of approximately $350 million and 4000 employees,
exports amounting to 45% of sales, and an annual growth rate which has been more than 10%
annually for many years. If we include the services industry (Telesat, Teleglobe and
Cancom) the annual space sales total is over $1 billion.

Finally, the fact that Alouette and its three successors
performed so well and much beyond expectations gave Canada an international reputation for
excellence in satellite design and engineering.

The Alouette/ISIS program produced a mountain of some
50,000 analogue tapes of topside sounder data. Is anyone going to digitise and preserve
these for the archives or they simply going to be thrown out? A question for the CSA and
perhaps DOC to ponder and on that note I will conclude my talk. Thank you."